Process and apparatus for removing sulfur compounds from hydrocarbon streams

Abstract

The invention is directed to a process for removal of sulfur compounds from a hydrocarbon source containing them, wherein the hydrocarbon source is to be utilized in a downstream hydrogen production process including, a sulfur removal step, said process for removal of sulfur compounds comprising passing the said hydrocarbon source through a low temperature sulfur trap, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature.

1 . Process for removal of sulfur compounds from a hydrocarbon source containing them, wherein the hydrocarbon source is to be utilized in a downstream hydrogen production process including a sulfur removal step, said process for removal of sulfur compounds comprising passing the said hydrocarbon source through a low temperature sulfur trap, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature.  
     
     
         2 . Process for removal of sulfur compounds from a hydrocarbon source containing them according to  claim 1 , said process for removal of sulfur compounds comprising passing the said hydrocarbon source through a low temperature sulfur trap, and a nickel containing high temperature sulfur trap, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature, said elevated temperature being above that at which nickel starts to adsorb sulfur compounds.  
     
     
         3 . Process according to  claim 1  or  2 , wherein the adsorption in the low temperature sulfur trap occurs at a temperature below 75° C.  
     
     
         4 . Process according to  claim 2 , wherein adsorption in the nickel occurs at a temperature above 65° C.  
     
     
         5 . Process according to claims  1 - 4 , wherein the desorption of sulfur compounds from the adsorbent in the low temperature sulfur trap occurs at temperatures above 80° C.  
     
     
         6 . Process according to claims  1 - 5 , wherein the said adsorbent in the said low temperature sulfur trap is selected from the group zeolites, carbon, clay materials, alumina, and silica-alumina.  
     
     
         7 . Process for the production of hydrogen from a hydrocarbon source containing sulfur compounds, said process comprising removal the said sulfur compounds from the said hydrocarbon source by passing the said hydrocarbon source consecutively through a low temperature sulfur trap, and a nickel containing high temperature sulfur trap, and converting the substantially sulfur free hydrocarbon source to hydrogen, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature, said elevated temperature being above that at which nickel starts to adsorb sulfur compounds.  
     
     
         8 . Process according to  claim 7 , wherein the said step of converting the hydrocarbon source to hydrogen is a steam reforming, or autothermal reforming.  
     
     
         9 . Process for the production of hydrogen from a hydrocarbon source containing sulfur compounds, said process comprising removing during startup the said sulfur compounds from the said hydrocarbon source by passing the said hydrocarbon source through a low temperature sulfur trap, and converting the hydrocarbon source to hydrogen in a high temperature sulfur resistant reforming step, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature, said low temperature sulfur trap being heated when the reforming unit is at its operating temperature.  
     
     
         10 . Process for generating electricity from fuel cell means, the fuel cell means comprising a stack of anodes and cathodes and having an anode side and a cathode side, each side dimensioned and configured for the passage of respective gas streams therethrough, the fuel cell means being fueled by a hydrogen-rich gas derived by converting a hydrocarbon source in a reformer, the improvement comprising passing the said hydrocarbon source consecutively through a low temperature sulfur trap, and a nickel containing high temperature sulfur trap, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature, said elevated temperature being above that at which nickel starts to adsorb sulfur compounds.  
     
     
         11 . Process for generating electricity from fuel cell means, the fuel cell means comprising a stack of anodes and cathodes and having an anode side and a cathode side, each side dimensioned and configured for the passage of respective gas streams therethrough, the fuel cell means being fueled by a hydrogen-rich gas derived by converting a hydrocarbon source in a high temperature sulfur resistant reformer, removing sulfur from the hydrogen-rich gas at elevated temperature by adsorption of the sulfur compounds in a sulfur trap, the improvement comprising passing the said hydrocarbon source through a low temperature sulfur trap, comprising an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature.  
     
     
         12 . Process according to  claim 10  or  11 , wherein the adsorption in the low temperature sulfur trap occurs at a temperature below 75° C.  
     
     
         13 . Process according to  claim 10 , wherein adsorption in the nickel occurs at a temperature above 65° C.  
     
     
         14 . Process according to claims  10 - 13 , wherein the desorption of sulfur compounds from the adsorbens in the low temperature sulfur trap occurs at temperatures above 80° C.  
     
     
         15 . Process according to claims  10 - 14 , wherein the said adsorbent in the said low temperature sulfur trap is selected from the group zeolites, carbon, clay materials, alumina, and silica-alumina.  
     
     
         16 . Process according to claims  10 , wherein the said nickel adsorbent and the said low temperature adsorbent are gradually heated during start-up of the hydrogen production unit and the fuel cell means.  
     
     
         17 . Process according to claims  10 - 16 , wherein the said step of converting the hydrocarbon source to hydrogen is a reforming step.  
     
     
         18 . Process of claims  10 - 17 , wherein said hydrocarbon source is a hydrocarbon source that contains sulfur compounds, more in particular a normally liquid hydrocarbon or natural gas.  
     
     
         19 . Process according to claims  10 - 18 , wherein the sulfur present in the sulfur compounds is substantially not part of aromatic ring.  
     
     
         20 . Use of an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at the said elevated temperature, during the start-up phase of a fuel cell or a hydrogen production unit, for removal of sulfur from hydrocarbon feed.  
     
     
         21 . Sulfur removal unit comprising at least one a low temperature sulfur trap, and at least one nickel containing high temperature sulfur trap, wherein the low temperature sulfur trap comprises an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at elevated temperature.  
     
     
         22 . Fuel cell system comprising 
 fuel cell means, the fuel cell means comprising a stack of anodes and cathodes and having an anode side and a cathode side, each side dimensioned and configured for the passage of respective gas streams therethrough,    means for producing a hydrogen-rich gas from a hydrocarbon source in a hydrogen production unit,    means for removing sulfur from the hydrocarbon feed at elevated temperature by adsorption of the sulfur compounds in a high temperature sulfur trap containing nickel material, and    means for removing sulfur during start-up phase upstream from the said high temperature sulfur trap containing nickel material, comprising a low temperature sulfur trap comprising an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at the said elevated temperature.    
     
     
         23 . Fuel cell system comprising a fuel cell means, the fuel cell means comprising a stack of anodes and cathodes and having an anode side and a cathode side, each side dimensioned and configured for the passage of respective gas streams therethrough, means for producing a hydrogen-rich gas from a hydrocarbon source in a sulfur resistant reforming unit, first means for removing sulfur from the hydrogen rich gas by adsorption of the sulfur compounds, and second means for removing sulfur during start-up phase upstream from the said means for producing a hydrogen-rich gas, for removing sulfur from the hydrogen rich, said second means comprising a low temperature sulfur trap comprising an adsorbent that adsorbs sulfur compounds at low temperature, and releases adsorbed sulfur at the said elevated temperature.